Savikivien

Savikivien is the Finnish term for claystones, a family of sedimentary rocks formed chiefly from clay-sized particles that have been compacted and cemented over time. In Finnish geology the word savikivi is used for the rock type, with savikivien serving as the genitive plural form. Claystones are among the finest-grained sedimentary rocks and are characterized by their very fine texture, often showing laminations or fissility.

Physically, savikivien are typically soft to moderately hard, depending on the degree of cementation. They usually have a low permeability because the pores between particles are very small. The color can vary from gray to brown or reddish hues, influenced by iron oxidation and the presence of other minerals such as quartz or calcite. The minerals are predominantly clay minerals—illite, kaolinite, and smectite—along with trace minerals.

Formation and distribution occur in quiet-water environments where fine clay particles settle from suspension. Deposition can take place in lakes, ponds, deltas, or deeper marine basins. Over geological time, burial and diagenesis compact and cement the clay-rich sediments into a cohesive rock. Claystones are commonly part of broader sedimentary sequences and are related to shales and mudstones.

The study of savikivien provides information about past depositional environments, sedimentation rates, and diagenetic histories. They are used in sedimentology and stratigraphy to interpret climate conditions and basin evolution, and in some cases may serve as a source of clay minerals for industrial use. See also claystone, mudstone, shale.